Alternating-current electric svsotor



2 Sheets-Sheet 1.

(No Model.)

THOMSON. ALTERNATING CURRENT ELECTRIC MOTOR.

Patented May 17, 1887.

INVENTOH fax, 1*

B) v m/fiak/i fi ATTORNEYS PEYERS. Plinto-Lilhngnphcr, Wnuhinghm ac.

2 sheets Sheet 2.

(No Model.)

B. THOMSON. ALTERNATING GURRENT ELEQTRIC MOTOR.

Patented May 17, 1887."

Tap 1% WITNESSES ATTOHNE YS N. PEYERS PhnluLilMgmphur. Walhingiun, DJA

- UNITED STATES PATENT WOFFICE.

ELIHU THOMSON, OF LYNN, MASSACHUSETTS.

ALTE'RNATlNG-CURRENT EILECTRlC MOTOR.

SPECIFICATION forming part of Letters Patent No. 363,185, dated May 17, 1887.

Application filed January 26, 1887. Serial No. 225,606. (No model.)

To all whont it may cmwern:

Be it known that I, ELIHU THOMSON, a citizen of the United States, and a resident of Lynn, in the county of Essex and State of Massachusetts, have invented a certain new and useful Alternating-Current Electric Motor, of which the following is a specification.

The object of this invention is to providea means whereby motive power for industrial or other uses may be developed from alternating electric currents.

My present invention depends upon the discovery made by me that through the induction exercised by an alternating current or magnetic field upon a closed circuit of low resistance and high selfinducti0n forming another coil or closed band and through the self-induction of the electric currents set up in the latter a repulsive action is established, resulting in a tendency of the closed circuit coil or conductor to move away from its inducingfield or to set itself at an angle to the inducingfield. This discovery forms the subject of another application for patent filed by me.

My present invention consists in a suitable combination of the'devices referred to with a commutator, as will be hereinafterdescribed, whereby, tlll'On-g. an alternating current, a continuous movement, oscillatory or rotary, may be produced in a similar way to that which is produced in ordinary electric motors by the operation of a continuous electric current.

In the accompanying drawings, Figures 1, 2, 3, 4., 5, 6, and 7 illustrate devices embodying the principle which I utilize in carrying out my present invention. Fig. 8 is a side elevation of an electric motor embodying my present invention. Fig. 9 is an end View of the same. Fig. 10 is a side view and section of a modification, and Fig. 11 is an end view of the same. Fig. 12 is a side view and section of an improved form of motor, and Fig. 13 is a section of a modified form of field-coil. Fig. 14 is a partialsection of an improved form of field-magnet, and Fig. 1.5 is a partial section on a line parallel to the shaft of the machine. Figs. 10, 17, 18, and 19 illustrate other modifications, which will. be referred to hereinafter.

In Fig. 1, P indicates a coil of insulated wire arranged to be traversed by alternating currents of moderate rapidity, and G is a cylinder or tube of copper or other good conducting metal encircling the coil or arranged in such inductive relation to the latter that stron g induced currents will be set up in the closed. circuit formed by the conductor C on the passsage of the alternating currents in the coilP. I have discovered that by this arrangement a strong tendency to movement of the conductor C in an axial line, or in the direction of the arrow at the upper part of the figure, is produced, which tendency is an apparently continuous one in the same direction, and not in first one and then in the] other direction, as might be expected. This action I believe is due to the self-induction of the currents ind need in the coil P,which self-induction causes them to be continued beyond the point of change of intensity and polarity in the inducinmaguetic field excited by the alternations in coil P, so that each induced current overlaps onto the succeeding inducing-current, whereby repulsion is produced at and near the position of maximum current in the two coils, while whatever attraction results occurs near the zero of current in both coils or circuits C 1. Either part being mounted, a tendency to movement in the direction of one or the other of the two arrows will result.

The effects are heightened by the employment of a core, as indicated at I, Fig. 2, consisting of a subdivided iron mass, such as a bundle of rods or bars of iron.

I find that the position of the coil P and corn (luctor 0 maybe reversed without changing the result. I find, also, that it is not nece. sary for one coil or conductor to encircle the other. For instance, the conductor C may be in the form of a ring presented, as shown in Fig. 3, to the coil P or to the magnetic field or mass acted upon by said coil.

It is best to make the conductor 0, which is of low resistance, in a laminated form, as indicated in Fig. at, where it is shown built up of a number of rings of copper or other good conducting material, which are suitablyinsulated from one another. The object of this is to confine the induced currents to circular paths whose plane is at right angles to the axis.

One of the coils or conductors may be mounted on a transverse or diametrical axis, as indicated in Fig. 5, in which case the movable coil will be deflected to a position (indicated by the lettei-K) at right angles to the plane of the other.

If. the two coils or conductors are exactly coincidentinplaneofcurrent,theywillremain at rest; but averyslight displacement will give rise to a contini'iance ot' the deflection on either side. In the present case the conductor of low resistance, is indicated as mounted on the axis 'i. The passage of alterm'iting current in the coil. 1 will cause a deflection, as indicated. The coil i might be the closed conductor and alternating currents be passed through the other ctmductor or circuit; with the san'ie effect.

In Fig. 0' a modifieat ion is indicated in which the alternating-current coil 1" is mounted so as to be movable. On the passage of alternating current it will be defiected to the position indicated by the letter K.

Ttis not necessary that the coils be concentric. Thus, for instance, as indicated in Fig. 7, the huninatcd subdivided ring or (OllflllCilOl' of. low resistanceis mounted on a diametrical axis transverse to the axis of:' coil l", and core I, thea'cfore, will, unless in a plane exactly par allel to that ot' coil 1, be turned to the position indicated by dotted lines K, in which it; is substantially at right angles to the coil 1 or the exciting mass of iron producingthe inducing magnetic field.

The closed (filClllikCOlltllltiiiOl may be oi any d esi red mate rial,and may,it' desired, be [formed from a coil of low-resistance conductor having its terminals properly connected to form the closed circuit. It required, increased.selfiinduction of the current in the low-resistance circuit may be secured by including an iron core (i1'1dicatedatG Fig. 19,) in a coil forming a portion of said circuit.

Having described some of the devices utilizcd in carrying out my present invention, 1 will proceed to a description of some of the forms of a complete a1' )aratus embed yiu'thc ctmibinations hereinafter claimed.

Referring to Fig. 8:, I have shown at i, in vertical cross-section, a coil of conducting wire connected with any suitable source of alternating currents and serving as the i nduct or or generator of a magnetic field first of one and then of. the otherpolarity, which shall act to set; up currents in the closed circuit conductor t. The latter consists of a coil or ringof metal of low specific resistance mounted on an axis diametrical to the coil 1. The mounting of theshai'toraxis tor the movable member( is a matterot mechanical detail, which may be varied in many ways. The detailsat present in vogue with the const ruetors of electric motors may be readily used. The conductor t consisting of a coil ot' wire or the like of a metal of low specific resistance, is connected by its terminals to the segmmits S S of a commutating ring, upon which bear brushes 1; l, electrically connected together, as indicated, by a bracket or support, 11 The brushes and the comnuitafor are so located that when the movable conductor (.1 is nearly parallel to the plane of the conductor-l, or is passed just beyond theplane of parallelism, thecirtaii tot t he conductor or conductors (J willbe closed in the path oi small. resistance between thebrushes l3 l3, and will continue to be so closed until the conductor has been repelled nearly or quite to a position at rightangles to the plane of coil P, when the short circuit is broken and the coil or conductor rotate! by its acquired momentum to parallelism again with the coil P,when its short circuit is again automatically closed by the brushes.

It is evident that it the conductor U be made as a ring of copper or of copper plates, instead of wire, it should be broken at some point of' its periphery aml the broken ends connected to the commutator segments S S by any dcsi red means. The connections may be effected in any of the ways well-known to constructors ol. electrical a iparz'ttus.

The details of construction ot the comm utator and other parts need not be set out l'ur ther, since the device at n'esent commonly used in electric motors will serve t he purposes of the invention.

In l igs. 8 and 9 that member of the mach i no in which the induced currents are set up is made the rotating or movable member. It is obvious, however, that such member might l e fixed, and that the part carrying the currents for setting up the inducing magnetic field might be made the movablemember ot'the machine, the commi'itator being properly applied to close the electric circuit thereto while the parts are moving under their mutual repulsive in fluence, and to break the circuit or remove the current from said coil when the coil has passed. to the position at right angles to thetixed member, and to keep it broken until the coil has moved again into the position Where repulsion will produce continuance of movement. Thus, as indiez'tted in Fig. to, the conductor 0, of. low specific resistance metal, and consisting of a coil or of a series of? plates, may be fixed, while the source of the z'ilternating magnetic field, consisting of the conductor l, may be mounted on a shaft and maybe connected with the source oli alteruating currents through a commutator ot' any suitable construction adapted to close the circuit ot' the coil I," when the two conductors are sulmtantially parallel, and to break said circuit or short-circuit the current from t he same when the conductor has swung around to a right-angled position, and to keep it broken until it. has ymsscd again into condition of parallelism or proper inductive relation to the fixed conductor.

The condnctor l" may include a core or mass of iron, I, consisting either of plat cs or wires,

which core may be stationary or may be mounted to revolve with the conductor l in any suitable manner. Fig.1] shows the conductor I aml its core mounted on the shaft and separated from the conductor t".

Several coils or conductors may take the place of the single conductor just described, just as in some forms of ordinary machine employin g a continuous current a series of armatures or conductors upon which the field acts sertatim are used to avoid the dead point. For an example of such a form of motor embodying my invention, reference may be had to Fig. 12. In this case a single exciting or inductive coil is used and a series of conductors or coils of low resistance acted upon in succession by the inducing field are used.

The armature or mass of iron I, consisting of laminze or wires, either stationary or revolving, is here indicated as surrounded by three coils capable of rotation as a system. These'coils are indicated at C C C and are severally connected to the segments 1 1, 2 2, and 3 3 of a commutator, upon Which bear the brushes 13 B, connected together. The obvious result of such construction, when the parts are properly adjusted, is that the coils or 0011- ductors will be successively short-circuited as they arrive in position substantially parallel with the plain of the coil P, and will be opencircuited when they arrive at a position at right angles thereto. Thus, as indicated, coil 0, which has just passed the position of parallelism, has just again had its circuit closed, and as the system revolves under the repulsive influences set up by the rapid alternations of current in P, the next coil, 0 is brought around to the same position and is brought into circuit, so that it in turn becomes the active propelling member, which brings the next coil into action.

Instead of a single coil P, two coils, as indicated in Fig. 13, may be employed, such coils having a gap between them for the passage of the shaft of the motor.

It is obvious that the-coil Pof Fig. 12 might be short-eirculated to form the closed con- (1 uctor, and that the brushes B B might be connected to the source of alternating currents, so as to introduce alternations successively into the sets of coils G G G which would then become the source of the exciting inductive field that would produce the induced currents of high self-induction in the coil P, the result being, as before, a mutual repulsion successively of the two members and a consequent. continuous rotation.

To increase the intensity of the inductive field, the coil P, carrying the alternating currents, can be surrounded, as indicated in Fig. 14, by a subdivided mass of iron partially enveloping the same transverse to its circumferential axis and consisting of iron wires, plates, or rods, the ends of which face the space in which the armature or rotary conductor revolves, so as to form the polepieces M M, Figs. 14c and 15, analogous to the pole-pieces of a dynamo-machine.

Instead of the wires applied as shown in Figs. 14 and 15, a series of plates of iron of the form indicated in Fig. 16 may be piled upon one another surrouinling the coil P, as indicated, and formin at their cent suitable presented to the revolving conductor in a similar manner to that indicated in Fig. 7, and serve to produce the alternating magnetic field, which shall act to induce currents first in one and then in the other direction in the revolving or movable conductors, an d produce thereby the repulsion between the field-producing devices and the conductors upon which the same acts inductively.

By means of a commutator as herein described a continuous rotary movement may be produced.

hat I claim as my invention is- 1. An electric motor consisting, essentially, of means for producing rapid alternations of magnetic field, a low-resistance conductor or a coil of good conducting metal in which currents of high self-induction may be induced by said alternations, and a commutator for alternately closing and breaking the circuit of one or the other member as the parts move into and out of inductive relation to one another.

2. The combination, substantially as described, of an a1ternating-current field-coil, a conductor or coil of metal of low specific resistance on normally short or closed circuit when in proper inductive relation to the field, and a commutator for breaking the circuit of said coil or of the exciting-coil for the mag netic field as the parts are moved out of proximity by the repulsive action of the induced currents in the low-resistance conductor, as and for the purpose described.

3. The combination, substantially as described, of an alternating-current field-coil, a rotary ring or coil of metal of low specific resistance in which induced currents are set up by the alternating magnetic field, and a commutator forcom pletin g the short circuit of the rotary ring or coil when in proper inductive position and breaking said short circuit as the conductor moves out of the field by the repulsive action established through the induced currents fiowing on short circuit.

4. The combination, substantially as described, of an alternating magnetic field, a se ries of low-resistance coils or conductors of meta-l of low specific resistance mounted on a suitable shaft, and a commutator for closing the short circuit of said coils or rings as each is moved into proper position in the inductive field by the conductor or conductors that are moved out of the field through the repulsive efiects due to the development of theinduced currents of high self-induction.

5. In an alternating-current electric motor,

IIO

1o axis.

Signed m; Lynn, in lho county of 'l lssex unrl Stale of Massziehusellas, this 21st (lay ole Junnnry, A. I). 1887.

A. L. Rommi-i, J. W. (lmnzonm'. 

